Work to continue fixing Seattle's Mercer Mess is prompting the Seattle Department of Transportation to close SR 99 and Mercer Street all weekend, which could cause some significant traffic tie-ups around the area.

Crews will be demolishing the east side of the SR 99 bridge over Mercer Street. The closure runs from Friday, July 5 at Midnight to Monday, July 8 at 5:00 a.m for the Mercer Corridor project.

SDOT says SR 99 will be fully closed between Valley Street and the southern end of the Battery Street Tunnel. Traffic traveling through Seattle via SR 99 will be directed to I-5 north of Seattle at 85th Street or south of Seattle at E Marginal Way and Spokane Street. More information about alternate routes during construction may be found at:

Pedestrian access will also be blocked on Mercer Street between 5th Avenue N and Dexter Avenue N during the weekend closure. Pedestrians will need to use the sidewalk on the north side of Broad Street to cross SR 99.

But the I-5 on- and off-ramps at Mercer Street and Broad Street will remain open during the weekend work.